Table of Contents
Journal of Astrophysics
Volume 2014 (2014), Article ID 817986, 12 pages
http://dx.doi.org/10.1155/2014/817986
Research Article

Numerical Experiments for Nuclear Flashes toward Superbursts in an Accreting Neutron Star

1Department of Physics, Kyushu University, Fukuoka 810-8560, Japan
2Kurume Institute of Technology, Fukuoka 830-0052, Japan
3Department of Physics, Hokkaido University, Sapporo 060-8810, Japan

Received 10 March 2014; Revised 20 June 2014; Accepted 20 June 2014; Published 23 July 2014

Academic Editor: Luciano Nicastro

Copyright © 2014 Masa-aki Hashimoto et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We show that the superburst would be originated from thermonuclear burning ignited by accumulated fuels in the deep layers compared to normal X-ray bursts. Two cases are investigated for models related to superbursts by following thermal evolution of a realistic neutron star: helium flash and carbon flash accompanied with many normal bursts. For a helium flash, the burst shows the long duration when the accretion rate is low compared with the observation. The flash could become a superburst if the burning develops to the deflagration and/or detonation. For a carbon flash accompanied with many normal bursts, after successive 2786 normal bursts during 1.81 × 109 s, the temperature reaches the deflagration temperature. This is due to the produced carbon which amount reaches to ≈0.1 in the mass fraction. The flash will develop to dynamical phenomena of the deflagration and/or detonation, which may lead to a superburst.